1. Field of the Invention
This invention is concerned with detergent compositions comprising olefin derived secondary alkyl sulphates and alcohol ethoxy sulphates and/or alcohol ethoxylates.
2. Description of the Prior Art
The invention is concerned with detergent compositions comprising secondary alkyl sulphates derived from olefins.
Secondary alkyl sulphates, usually in the form of alkali-metal, ammonium or amine salts, may be derived from both olefins and alcohols using sulphuric acid, followed by neutralization with the appropriate base, although olefin-derived secondary alkyl sulphates have not been so extensively investigated as alcohol-derived secondary alkyl sulphates, because the preparation of the former is usually more difficult than the preparation of the latter. The only olefin-derived secondary alkyl sulphate which has achieved a significant commercial success is "Teepol" 10 ("Teepol" is a registered Trade Mark) which is derived from sulphation and neutralization of C.sub.8 to C.sub.18 .alpha.-olefins. Although this product has been commercially available for about 30 years it has not been extensively investigated as a component of house-hold products such as high-performance fabric and dish-washing compositions, because of its poor detergency although it has been used in industrial products either alone or in binary blends with alkylbenzene sulphonates.
The increased availability of narrower cuts, or single cuts, of both alpha- and internal olefins, in the C.sub.10 to C.sub.18 range, particularly in the C.sub.11 to C.sub.17 range, has renewed interest in olefin-derived secondary alkyl sulphates as components of house-hold products.
However, insofar as C.sub.10 to C.sub.18 internal olefins are concerned, the performance of the secondary alkyl sulphates derived therefrom, although better than that of secondary alkyl sulphates derived from C.sub.8 to C.sub.18 alpha-olefins, has proved disappointing.
Insofar as secondary alkyl sulphates derived from C.sub.10 to C.sub.18 alpha-olefins are concerned it has been found that the performance thereof depends on the structure of the resulting secondary alkyl sulphates. It is possible to prepare from these olefins, by using low reaction temperatures, such as temperatures of below 15.degree. C, e.g. of between -5.degree. C and 5.degree. C, and/or low residence times such as times of below 10 minutes, e.g. of from 4 to 8 minutes, secondary alkyl sulphates in which the sulphate groups are predominately on the 2- and 3- carbon atoms of the alkyl chains (hereinafter referred to as high crystalline fraction) and the performance of these products is encouraging and is much better than the performance of secondary alkyl sulphates derived from C.sub.10 to C.sub.18 internal olefins.
It is also possible to prepare from these C.sub.10 to C.sub.18 alpha-olefins, by using higher reaction temperatures such as temperatures above 15.degree. C, e.g. of between 25.degree. and 35.degree. C, and/or high residence times such as times above 10 minutes, e.g. of from 10 to 15 minutes, secondary alkyl sulphates in which the sulphate groups are more randomly distributed over the alkyl chains (hereinafter referred to as low crystalline fraction) but the performance of these products has also proved disappointing and is no better than secondary alkyl sulphates derived from C.sub.10 to C.sub.18 internal olefins. This equivalency in performance between low crystalline fraction secondary alkyl sulphates and secondary alkyl sulphates derived from C.sub.10 to C.sub.18 internal olefins results from the fact that the latter is also a low crystalline fraction, irrespectively of the reaction conditions such as the temperature, under which they are prepared, i.e. there is no predominance of 2- and 3-isomer content as in high crystalline fraction secondary alkyl sulphate.